Systems and methods for optimizing simulcast streams in group video calls

ABSTRACT

Systems, methods, and non-transitory computer-readable media can identify a set of participants in a group video call, wherein each participant is associated with an uplink capacity and a downlink capacity, and the set of participants includes a set of sender participants and a set of subscriber participants. For a first sender participant of the set of sender participants, one or more video stream layers to be uploaded by the first sender participant are determined based on downlink capacities of one or more subscriber participants of the set of subscriber participants. Each subscriber participant of the one or more subscriber participants is assigned to receive one video stream layer of the one or more video stream layers to be uploaded by the first sender participant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/885,696, filed on Jan. 31, 2018 and entitled “SYSTEMS AND METHODS FOROPTIMIZING SIMULCAST STREAMS IN GROUP VIDEO CALLS”, which isincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present technology relates to the field of digital communications.More particularly, the present technology relates to techniques foroptimizing simulcast streams in group video calls.

BACKGROUND

Today, people often utilize computing devices for a wide variety ofpurposes. Users can use their computing devices, for example, tocommunicate with other users. Such communications are increasinglypopular over a social networking system. Digital communications, such asthose on a social networking system, may involve various types ofcommunication. Some types of digital communication allow a user toengage in focused exchanges. For example, the user may target aparticular user or users through the use of a messaging system or anemail system supported by a social networking system. As anotherexample, the user can enter into audio communications or videocommunications with other users.

In many instances, video communications can be preferred by usersbecause video communications can allow the users to most effectivelyconvey information and simulate real life communications. In someinstances, two participants in different locations can engage in videocommunications. It also can be desirable to allow a group of users inmultiple locations to use video communications to facilitatecommunications among the group.

SUMMARY

Various embodiments of the present disclosure can include systems,methods, and non-transitory computer readable media configured toidentify a set of participants in a group video call, wherein eachparticipant is associated with an uplink capacity and a downlinkcapacity, and the set of participants includes a set of senderparticipants and a set of subscriber participants. For a first senderparticipant of the set of sender participants, one or more video streamlayers to be uploaded by the first sender participant are determinedbased on downlink capacities of one or more subscriber participants ofthe set of subscriber participants. Each subscriber participant of theone or more subscriber participants is assigned to receive one videostream layer of the one or more video stream layers to be uploaded bythe first sender participant.

In an embodiment, the one or more video stream layers to be uploaded bythe first sender participant are determined based on downlink capacitiesof subscriber participants subscribed to the first sender participant.

In an embodiment, each subscriber participant is subscribed to at leastone sender participant.

In an embodiment, each video stream layer to be uploaded by the firstsender participant is associated with a bitrate.

In an embodiment, a bitrate is determined for each video stream to beuploaded by the first sender participant based on downlink capacities ofsubscriber participants subscribed to the first sender participant andthe uplink capacity associated with the first sender participant.

In an embodiment, the set of sender participants are ranked based onuplink capacity.

In an embodiment, the determining for a first sender participant of theset of sender participants one or more video stream layers to beuploaded by the first sender participant further comprises determining,for each sender participant of the set of sender participants, one ormore video stream layers to be uploaded by the sender participants basedon downlink capacities of subscriber participants subscribed to thesender participant.

In an embodiment, the determining, for each sender participant of theset of participants, one or more video stream layers to be uploaded bythe sender participant comprises iteratively processing each senderparticipant in an order based on the ranking.

In an embodiment, the iteratively processing each sender participantcomprises a plurality of iterations, with each iteration beingassociated with a particular sender participant of the set of senderparticipants, and each iteration comprises iteratively processing eachsubscriber participant subscribed to the particular sender participantassociated with the iteration.

In an embodiment, the iteratively processing each subscriber participantsubscribed to the particular sender participant comprises determining,for each subscriber participant, whether to create a new layer to beuploaded by the particular sender participant or assigning thesubscriber participant to a previously created layer associated with theparticular sender participant.

It should be appreciated that many other features, applications,embodiments, and/or variations of the disclosed technology will beapparent from the accompanying drawings and from the following detaileddescription. Additional and/or alternative implementations of thestructures, systems, non-transitory computer readable media, and methodsdescribed herein can be employed without departing from the principlesof the disclosed technology.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example system including a group video callmodule, according to an embodiment of the present disclosure.

FIG. 2 illustrates example pseudocode associated with automatedbandwidth allocation, according to an embodiment of the presentdisclosure.

FIG. 3 illustrates example pseudocode associated with automated downlinkcapacity reservation, according to an embodiment of the presentdisclosure.

FIGS. 4A-4Q illustrate an example scenario associated with group videocall simulcast optimization, according to an embodiment of the presentdisclosure.

FIG. 5 illustrates an example method associated with group video callsimulcast optimization, according to an embodiment of the presentdisclosure.

FIG. 6 illustrates a network diagram of an example system including anexample social networking system that can be utilized in variousscenarios, according to an embodiment of the present disclosure.

FIG. 7 illustrates an example of a computer system or computing devicethat can be utilized in various scenarios, according to an embodiment ofthe present disclosure.

The figures depict various embodiments of the disclosed technology forpurposes of illustration only, wherein the figures use like referencenumerals to identify like elements. One skilled in the art will readilyrecognize from the following discussion that alternative embodiments ofthe structures and methods illustrated in the figures can be employedwithout departing from the principles of the disclosed technologydescribed herein.

DETAILED DESCRIPTION Optimizing Size of Simulcast Strems in Group VideoCalls

As mentioned, people often utilize computing devices for a wide varietyof purposes. Users can use their computing devices, for example, tocommunicate with other users. Such communications are increasinglypopular over a social networking system. Digital communications, such asthose on a social networking system, may involve various types ofcommunication. Some types of digital communication allow a user toengage in focused exchanges. For example, the user may target aparticular user or users through the use of a messaging system or anemail system supported by a social networking system. As anotherexample, the user can enter into audio communications or videocommunications with other users.

In many instances, video communications can be preferred by usersbecause video communications can allow the users to most effectivelyconvey information and simulate real life communications. In someinstances, two participants in different locations can engage in videocommunications. It also can be desirable to allow a group of users inmultiple locations to use video communications to facilitatecommunications among the group.

Conventional approaches specifically arising in the realm of computertechnology include digital communications in which a plurality of usersparticipate in a group video call. Generally, video streams from one ormore participants in a group video call are transmitted to the otherparticipants in substantially real-time. Participants in a group videocall may be able to request varying levels of video quality. Forexample, participants can request a high quality stream, a standardquality stream, or a low quality stream. However, it is possible that aparticipant may request a video stream of a higher quality than theirnetwork connection is optimally suited to provide. For example, a usermay request a high quality video stream even if the user's networkconnection is not optimally suited to provide a high quality videostream. In such scenarios, certain conventional approaches have opted tolimit video stream bitrates based on a participant with the lowestavailable downlink capacity. For example, consider an example scenarioin which there are four participants in a group video call. Three of thefour participants may request a high quality video stream from thefourth participant. However, a first participant of the threeparticipants has a downlink capacity of 100 kbps, while the second andthird participants each have a much greater downlink capacity of 5 Mbps.Under certain conventional approaches, the bitrate and/or quality of thehigh quality video stream uploaded by the fourth participant may berestricted to be less than 100 kbps so as to accommodate the firstparticipant with the 100 kbps downlink capacity. All three participantsrequesting the high quality video stream receive the limited highquality video stream due to the first participant's low downlinkcapacity. This leads to the undesirable outcome that other participantsin a group video call may be unnecessarily forced to receive a lowerquality video stream even if they are capable of receiving a higherquality video stream and the uploading user is capable of uploading ahigher quality video stream. Such approaches could even lead toscenarios in which a “high quality” stream has a lower quality than a“low quality” stream depending on which users have requested whichstream. For example, in the above example scenario, if the thirdparticipant, who has a 5 Mbps downlink capacity, had requested a lowquality video stream, it is possible that the low quality video streamwould be of a higher quality than the high quality video stream becausethe first participant is limiting the high quality video stream.

Other conventional approaches have divided each uploading participant'suplink capacity into pre-determined ratios for video streams of variousqualities. For example, a participant's uplink capacity may be dividedsuch that 80% of the uplink capacity is used for a high quality stream,15% of the uplink capacity is reserved for a medium quality stream, and5% of the uplink capacity is reserved for a low quality stream. However,this approach fails to account for the particular characteristics of theusers that are participating in a group video call. Therefore, suchapproaches, fail to optimize user experience based on the particulargroup of participants participating in a group video call.

An improved approach rooted in computer technology overcomes theforegoing and other disadvantages associated with conventionalapproaches specifically arising in the realm of computer technology. Ingeneral, a set of participants participating in a group video call canbe identified. For example, the set of participants may be identified bya central server tasked with managing the group video call. Eachparticipant in the set of participants can be associated with an uplinkcapacity and a downlink capacity. One or more of the participants may beidentified as sender participants that will be uploading one or morevideo streams to be received and viewed by other participants in thegroup video call. One or more participants may be identified assubscriber participants that will be receiving and viewing at least onevideo stream uploaded by another participant. A given participant in agroup video call may be solely a sender participant, solely a subscriberparticipant, or both a sender and a subscriber participant. Each senderparticipant in the set of participants can be instructed to upload oneor more video stream layers of varying qualities (e.g., bitrates). Thenumber of video stream layers to be uploaded by a sender participant anda bitrate associated with each video stream layer may be determinedbased on the uplink capacity of the sender participant and the downlinkcapacities of other participants in the group video call. Thisdetermination may be made, for example, by the central server. Forexample, the central server may instruct a first participant to upload afirst video stream layer having a first quality (e.g., a first bitrate)and a second video stream layer having a second quality (e.g., a secondbitrate). The first and second video stream layers, and the first andsecond bitrates, may be determined based on the first participant'suplink capacity and based on the downlink capacities of otherparticipants in the group video call. Determination of video streamlayers and bitrates may be performed iteratively until each senderparticipant is assigned one or more video stream layers to be uploadedby that sender participant. When the iterations have completed, eachsender participant is associated with one or more video stream layersthat he or she is responsible for uploading, and each subscriberparticipant is associated with one video stream layer from each of oneor more sender participants that the subscriber participant willreceive. In certain embodiments, each participant in a group video callcan be communicatively connected to a central server. The central servercan be configured to receive video stream layers from one or more senderparticipants, and to transmit the video stream layers to one or moresubscriber participants based on their subscriptions. More detailsrelating to the disclosed technology are provided below.

FIG. 1 illustrates an example system 100 including a group video callmodule 102, according to an embodiment of the present disclosure. Thegroup video call module 102 can be configured to identify a set ofparticipants participating in a group video call. Each participant inthe set of participants can be associated with an uplink capacity and adownlink capacity. One or more of the participants may be identified assender participants. Sender participants are those participants thatwill be uploading one or more video streams to be received and viewed byother participants in the group video call. One or more participants maybe identified as subscriber participants. Subscriber participants arethose participants that have will be receiving and viewing at least onevideo stream uploaded by another participant. A given participant in agroup video call may be solely a sender participant, solely a subscriberparticipant, or both a sender and a subscriber participant. Subscriberparticipants can be associated with one or more subscriptions. Eachsubscription can be associated with a subscriber participant and asender participant, and a subscription can indicate that the subscriberparticipant has requested and/or will be receiving a video stream (alsoreferred to herein as a “video stream layer”) uploaded by the senderparticipant. Each subscription may also be associated with a qualitysetting or quality indicator, indicating a quality of a video streamrequested by a subscriber participant. For example, a subscriptionbetween a subscriber participant and a sender participant can indicatewhether the subscriber participant has requested a high quality videostream layer, a standard quality video stream layer, or a low qualityvideo stream layer from the sender participant.

For each sender participant in the set of participants, the group videocall module 102 can determine one or more video stream layers to beuploaded by that sender participant based on the uplink capacity of thesender participant and the downlink capacities of other participants(e.g., subscriber participants) in the group video call. Each videostream layer uploaded by a particular sender participant may have and/orbe associated with a particular quality (e.g., a particular bitrate).For example, for a first sender participant in the set of participants,the group video call module 102 can review an uplink capacity of thefirst sender participant and downlink capacities for each subscriberparticipant that has subscribed to the first sender participant (e.g.,each subscriber participant that will be receiving a video stream fromthe first sender participant as part of the group video call). Based onthese factors, the group video call module 102 can instruct the firstsender participant (i.e., a computing device associated with the firstsender participant) to upload a first video stream layer having a firstquality (e.g., a first bitrate), a second video stream layer having asecond quality (e.g., a second bitrate), and so forth. In variousembodiments, additional considerations may be taken into account whendetermining how many streams each sender participant will upload, and atwhat bitrates. These additional considerations can include, for example,capabilities of a sender participant, such as CPU speed, GPU processingspeed, other hardware performance metrics or capabilities, and the like.

The group video call module 102 can iteratively cycle through eachsender participant in the group video call and determine video streamlayers to be uploaded by each sender participant until suchdetermination has been made for every sender participant in the groupvideo call. In various embodiments, when the iterative processing by thegroup video call module 102 has completed, each sender participant isassociated with one or more video stream layers that he or she isresponsible for uploading. Additionally, when the iterative processinghas completed, each subscriber participant is associated with one videostream layer from each sender participant to which the subscriberparticipant is subscribed. For example, consider an example scenario inwhich there are three participants in a group video call, eachparticipant is a sender participant, and each participant is alsosubscribed to every other participant. Each participant may beinstructed to upload one or more video stream layers, with each videostream layer having a particular bitrate. A first participant may beassigned to receive a particular video stream layer from a secondparticipant and a particular video stream layer from a thirdparticipant, the second participant may be assigned to receive aparticular video stream layer from the first participant and aparticular video stream layer from the third participant, and the thirdparticipant may be assigned to receive a particular video stream layerfrom the first participant and a particular video stream layer from thesecond participant. Assignment of a subscriber participant to particularvideo stream layers uploaded by sender participants may be determinedbased on the subscriber participant's downlink capacity and the senderparticipants' uplink capacities. The group video call module 102 can beconfigured to receive video stream layers from each sender participantin a group video call, and to transmit the video stream layers tosubscriber participants in the group video call based on assignments ofparticular subscriber participants to particular video stream layers. Invarious embodiments, one or more functions of the group video callmodule 102 can be implemented in a central server. The participants of agroup video call can be connected to the central server and can uploadvideo stream layers to the central server and receive from the centralserver video stream layers uploaded by other participants. Althoughvarious embodiments of the present disclosure will describe variousconcepts with reference to group video calls, it should be understoodthat the present disclosure may be applied to any exchange of datastreams, such as audio data, video data, other media, and the like.

As shown in the example of FIG. 1, the group video call module 102 caninclude a participant information module 104, a bandwidth allocationmodule 106, and a video call module 108. In some instances, the examplesystem 100 can include at least one data store 110. The components(e.g., modules, elements, etc.) shown in this figure and all figuresherein are exemplary only, and other implementations may includeadditional, fewer, integrated, or different components. Some componentsmay not be shown so as not to obscure relevant details. In variousembodiments, one or more of the functionalities described in connectionwith the group video call module 102 can be implemented in any suitablecombinations.

In some embodiments, the group video call module 102 can be implemented,in part or in whole, as software, hardware, or any combination thereof.In general, a module as discussed herein can be associated withsoftware, hardware, or any combination thereof. In some implementations,one or more functions, tasks, and/or operations of modules can becarried out or performed by software routines, software processes,hardware, and/or any combination thereof. In some cases, the group videocall module 102 can be, in part or in whole, implemented as softwarerunning on one or more computing devices or systems, such as on a serversystem or a client computing device. In some instances, the group videocall module 102 can be, in part or in whole, implemented within orconfigured to operate in conjunction with or be integrated with a socialnetworking system (or service), such as a social networking system 630of FIG. 6. Likewise, in some instances, the group video call module 102can be, in part or in whole, implemented within or configured to operatein conjunction with or be integrated with a client computing device,such as the user device 610 of FIG. 6. For example, the group video callmodule 102 can be implemented as or within a dedicated application(e.g., app), a program, or an applet running on a user computing deviceor client computing system. The application incorporating orimplementing instructions for performing functionality of the groupvideo call module 102 can be created by a developer. The application canbe provided to or maintained in a repository. In some cases, theapplication can be uploaded or otherwise transmitted over a network(e.g., Internet) to the repository. For example, a computing system(e.g., server) associated with or under control of the developer of theapplication can provide or transmit the application to the repository.The repository can include, for example, an “app” store in which theapplication can be maintained for access or download by a user. Inresponse to a command by the user to download the application, theapplication can be provided or otherwise transmitted over a network fromthe repository to a computing device associated with the user. Forexample, a computing system (e.g., server) associated with or undercontrol of an administrator of the repository can cause or permit theapplication to be transmitted to the computing device of the user sothat the user can install and run the application. The developer of theapplication and the administrator of the repository can be differententities in some cases, but can be the same entity in other cases. Itshould be understood that many variations are possible.

The group video call module 102 can be configured to communicate and/oroperate with the at least one data store 110, as shown in the examplesystem 100. The data store 110 can be configured to store and maintainvarious types of data. In some implementations, the data store 110 canstore information associated with the social networking system (e.g.,the social networking system 630 of FIG. 6). The information associatedwith the social networking system can include data about users, useridentifiers, social connections, social interactions, profileinformation, demographic information, locations, geo-fenced areas, maps,places, events, pages, groups, posts, communications, content, feeds,account settings, privacy settings, a social graph, and various othertypes of data. In some embodiments, the data store 110 can storeinformation that is utilized by the group video call module 102. Forexample, the data store 110 can store various rules for video streamlayer creation and/or bandwidth allocation in group video calls, groupvideo call subscription information, user characteristics such asdownlink capacity and uplink capacity, and the like. It is contemplatedthat there can be many variations or other possibilities.

The participant information module 104 can be configured to identify aset of participants participating in a group video call. Eachparticipant can be associated with an uplink capacity and a downlinkcapacity. The participant information module 104 can be configured todetermine the uplink and downlink capacities of each participant or toreceive this information from another source.

The participant information module 104 can also be configured to receivesubscription information for the participants in a group video call. Asdiscussed, one or more participants in a group video call may beidentified as sender participants that will upload one or more videostream layers to be received and viewed by other participants in thegroup video call. Furthermore, one or more participants in a group videocall may be identified as subscriber participants that will receive andview one or more video stream layers uploaded by other participants inthe group video call. A given participant may be both a senderparticipant and a subscriber participant. For example, in a group videocall in which every participant is uploading a video stream, and is alsoviewing video streams of all other participants in the group video call,every participant is both a sender participant and a subscriberparticipant.

Subscription information received by the participant information module104 may identify which subscriber participants are subscribed to whichsender participants in a group video call. Subscription information mayalso include quality information indicating a requested quality levelfor each subscription between a subscriber participant and a senderparticipant. For example, the quality information may indicate whetherthe subscriber participant has requested a high quality video streamlayer, a standard quality video stream layer, or a low quality videostream layer from a particular sender participant.

In certain embodiments, quality information for a subscription may beinput directly by a participant. For example, a subscriber participantmay select an option in a user interface which specifies the qualitylevel the subscriber participant would like to receive. In certainembodiments, quality information for a subscription may be inferred. Ina particular instance of this embodiment, quality information can beinferred based on a viewing mode of a subscriber participant. Forexample, if a subscriber participant has a first sender participant in afull-screen view and all remaining sender participants in thumbnailviews, it may be inferred that the subscriber participant would like ahigh quality video stream from the first sender participant, and lowquality video streams from the remaining sender participants. In anotherexample, if a subscriber participant has all sender participants in agrid view such that the sender participants are displayed in tiles ofsubstantially equal sizes, it can be inferred that the subscriberparticipant would like a medium quality video stream from each senderparticipant. In another instance of this embodiment, quality informationcan be inferred based on group video call equipment being utilized by asubscriber participant and/or a sender participant. Group video callequipment can include hardware and/or software components. For example,if a subscriber participant is connected to a group video call usinghigh-end dedicated video conferencing equipment, it can be assumed thatthe subscriber participant would like to receive a highest quality videostream layer available from each sender participant.

The bandwidth allocation module 106 can be configured to determine, foreach sender participant in a group video call, one or more video streamlayers to be uploaded by the sender participant based on the senderparticipant's uplink capacity and downlink capacities of otherparticipants in the group video call. The bandwidth allocation module106 can also be configured to determine a quality level (e.g., abitrate) for each video stream layer based on the sender participant'suplink capacity and downlink capacities of other participants in thegroup video call. In certain embodiments, the one or more video streamlayers to be uploaded by a sender participant and their respectivebitrates may be determined based on the downlink capacities of thesubscriber participants that are subscribed to the sender participant.

The bandwidth allocation module 106 can also be configured to assigneach subscriber participant in a group video call to receive one videostream layer from each sender participant in the group video call towhich the subscriber participant is subscribed. By assigning asubscriber participant to a particular video stream layer uploaded by asender participant, the bandwidth allocation module 106 determines thatthe subscriber participant will receive from the sender participant avideo stream layer having a particular bitrate.

In various embodiments, the bandwidth allocation module 106 candetermine video stream layers to be uploaded by sender participants in agroup video call in an iterative fashion. For example, a set of senderparticipants can be ordered and/or ranked based on ranking criteria, andthe bandwidth allocation module 106 can process each sender participantsequentially based on the order. As each sender participant is beingprocessed, the bandwidth allocation module 106 can determine one or morevideo stream layers to be uploaded by the sender participant as well asquality levels (e.g., bitrates) for each video stream layer, and canassign each subscriber participant that is subscribed to the senderparticipant to receive a particular video stream layer of the one ormore video stream layers. In one embodiment, the bandwidth allocationmodule 106 can rank the set of sender participants based on uplinkcapacity in ascending order from lowest uplink capacity to highestuplink capacity. The bandwidth allocation module 106 can sequentiallyprocess the sender participants based on the ranking. For example, thebandwidth allocation module 106 can first process a first senderparticipant having a lowest uplink capacity, and determine one or morevideo stream layers to be uploaded by the first sender participant andbitrates for the one or more video stream layers based on the firstsender participant's uplink capacity and downlink capacities ofsubscriber participants subscribed to the first sender participant. Thebandwidth allocation module 106 can then process a second senderparticipant having a second lowest uplink capacity, and determine one ormore video stream layers to be uploaded by the second sender participantand bitrates for the video stream layers based on the second senderparticipant's uplink capacity and downlink capacities of subscriberparticipants subscribed to the second sender participant, and so forth,until all sender participants have been processed. Once the iterativeprocessing of all sender participants has completed, each senderparticipant is tasked with uploading one or more video stream layershaving specified bitrates, and each subscriber participant is assignedto receive one video stream layer from each sender participant to whichthe subscriber participant is subscribed.

In various embodiments, the processing performed by the bandwidthallocation module 106 can be repeated periodically and/orintermittently. For example, in certain embodiments, the processingperformed by the bandwidth allocation module 106 can be performedperiodically at a regular time interval (e.g., every two seconds) basedon updated participant information (e.g., an updated set ofparticipants, updated uplink capacities, updated downlink capacities,updated subscription information, etc.). In certain embodiments, theprocessing performed by the bandwidth allocation module 106 can berepeated and/or updated based on particular events. For example, theprocessing performed by the bandwidth allocation module 106 can berepeated based on updated participant information each time aparticipant joins a group video call and/or each time a participantleaves a group video call.

For clarity of understanding, various features of the bandwidthallocation module 106 corresponding to various embodiments of thebandwidth allocation module 106 will be described in greater detailherein with reference to example sets of pseudocode 200 and 300 depictedin FIG. 2 and FIG. 3, respectively.

The video call module 108 can be configured to manage a group videocall. As discussed, a group video call can have a plurality ofparticipants, including one or more sender participants and one or moresubscriber participants. The plurality of participants can be subscribedto one another in various combinations. As described above, for at leasta subset of the plurality of participants (i.e., a set of senderparticipants), the bandwidth allocation module 106 can determine foreach sender participant one or more video stream layers to be uploadedby the sender participant and a bitrate for each video stream layer. Thevideo call module 108 can be configured to receive video stream layersuploaded by the each sender participant in a group video call.Furthermore, as described above, for at least a subset of the pluralityof participants (i.e., a set of subscriber participants), the bandwidthallocation module 106 can assign each subscriber participant to receiveone video stream layer from each sender participant to which thesubscriber participant is subscribed. The video call module 108 cantransmit appropriate video streams (i.e., video stream layers) to eachsubscriber participant based on video stream layer assignments asdetermined by the bandwidth allocation module 106.

FIG. 2 illustrates example pseudocode 200 for implementing variousfunctions and features of the bandwidth allocation module 106, accordingto an embodiment of the present disclosure. It should be understood thatthe pseudocode 200 implements a particular embodiment, but the presentdisclosure is not limited to this embodiment and many variations arepossible. The pseudocode 200 takes as an input a list of participants ina group video call (also referred to as “endpoints”), an uplink capacityfor each participant, and a downlink capacity for each participant. Thefunction can also receive as an input a set of “subscriptions” betweenthe various participants.

At line 204 of the pseudocode 200, the set of participants are sorted inascending order based on uplink capacity. In different embodiments, thebandwidth allocation module 106 can be configured to rank and/or orderthe set of participants based on different ordering or ranking criteria.

Lines 205-237 implement a first iterative sequence in which eachparticipant that is identified as a sender participant is processedsequentially based on the ranked order of the participants. For example,in this example embodiment, the first iteration will process a firstsender participant with a lowest uplink capacity, the second iterationwill process a second sender participant with a second lowest uplinkcapacity, and so forth, until all sender participants have beenprocessed. Each iteration of the first iterative sequence will bedescribed with reference to a “sender participant” that is beingprocessed in that iteration and one or more “subscriber participants”that are subscribed to that sender participant.

At lines 206-208, a set of subscriber participants that are subscribedto the sender participant are identified. At lines 209-210, a “reserveddownlink” is determined for each subscriber participant in the set ofsubscriber participants. Each subscriber participant's reserved downlinkis determined using a function “ComputeReservedDownlink.” Determinationof reserved downlinks for each subscriber participant will be describedin greater detail with reference to FIG. 3. At this juncture, it issufficient to say that a subscriber participant's reserved downlinkrepresents a portion of the subscriber participant's available downlinkcapacity that is temporarily reserved for the sender participant beingprocessed. At line 212, each subscriber participant that is subscribedto the sender participant is ranked in ascending order based on reserveddownlink.

Lines 213 and 214 initialize two values “prev_layer_kbps” and“current_layer_to_upload” to be used in a second iterative sequenceimplemented in lines 215-231. The second iterative sequence iterativelyprocesses each subscriber participant subscribed to the senderparticipant being processed in the current iteration of the firstiterative sequence. In this example embodiment, each subscriberparticipant is processed sequentially in order from lowest reserveddownlink to highest reserved downlink. The second iterative sequencewill be described with reference to a “current subscriber participant”being processed in a particular iteration of the second iterativesequence, and a “current sender participant” being processed in aparticular iteration of the broader, first iterative sequence. At line216, a value “current_layer_kbps” is set equal to the lesser of thecurrent subscriber participant's reserved downlink and the currentsender participant's remaining uplink capacity. The value“current_layer_kbps” represents a size of a potential new video streamlayer that may be created for and/or assigned to the current senderparticipant.

At lines 217-222, a determination is made as to whether or not to createa new video stream layer for the current sender participant based on aminimum difference threshold. At line 217, a determination is made as towhether a size of a potential new video stream layer(current_layer_kbps) satisfies a minimum difference threshold withrespect to a previous video stream layer. In this particular embodiment,a determination is made as to whether the size of the potential newvideo stream layer is at least two times larger than the previous videostream layer (prev_layer_kbps). If yes, the current_layer_to_uploadcounter is incremented (line 218), and a new video stream layer iscreated for the sender participant (line 219). The new video streamlayer has a bitrate equal to current_layer_kbps (line 219). At line 220,the new video stream layer's bitrate is subtracted from the currentsender participant's available uplink capacity. At line 230, the currentsubscriber participant is mapped to the newly created video streamlayer. In other words, the current subscriber participant will receivethe newly created video stream layer having a bitrate equal tocurrent_layer_kbps from the current sender participant.

However, if the potential new video stream layer (current_layer_kbps)does not satisfy the minimum difference threshold, i.e., is not at leasttwo times larger than the previous video stream layer, then no new layeris created, and the current subscriber participant is mapped to aprevious video stream layer (lines 221, 222, and 230).

As discussed, lines 215-230 of pseudocode 200 iteratively process eachsubscriber participant subscribed to a current sender participant. Foreach subscriber participant, the bitrate allocation module 106determines a size of a potential new video stream layer that could becreated (current_layer_kbps). The size of the potential new video streamlayer is either equal to a current subscriber participant's reserveddownlink or, if the current sender participant does not have sufficientremaining uplink to satisfy the current subscriber participant'sreserved downlink, the size of the potential new video stream layer isequal to the current sender participant's remaining uplink capacity(line 216). The bitrate allocation module 106 determines whether thepotential new video stream layer warrants creation of a new video streamlayer to be uploaded by the sender participant, or whether the currentsubscriber participant should be assigned to a previously created videostream layer. This determination may be made based on a differencethreshold between the size of the potential new video stream layer and abitrate of a previously created video stream layer. In the examplepseudocode 200, this difference threshold is defined such that thepotential new video stream layer must be at least twice as large as aprevious video stream layer (line 217). In other embodiments, differentdifference thresholds may be used. For example, the difference thresholdmay be any multiple or an absolute difference (e.g., 100 kbps greaterthan a previous video stream layer), or a combination thereof. Incertain embodiments, multiple difference thresholds may be defined, forexample, for different ranges of bitrates. If the potential new videostream layer satisfies the difference threshold, then a new video streamlayer is created with a bitrate equal to the size of the potential newvideo stream layer (line 219), and the current subscriber participant isassigned to the new video stream layer (line 230). The current senderparticipant's remaining uplink capacity is also updated by subtractingthe size of the new video stream layer (line 220). If the potential newvideo stream layer does not satisfy the difference threshold, thecurrent subscriber participant is assigned to a previous video streamlayer (i.e., a video stream layer that has already been created andassigned to the current sender participant) (lines 221, 222, and 230).

Once the second iterative sequence implemented in lines 215-231completes processing of a set of subscriber participants subscribed to acurrent sender participant, the current sender participant has beenassigned one or more video stream layers to be uploaded by the senderparticipant, with each video stream layer having a particular bitrate.For example, a sender participant may be assigned with uploading a firstvideo stream layer having a bitrate of 100 Kbps, a second video streamlayer having a bitrate of 500 Kbps, and a third video stream layerhaving a bitrate of 1 Mbps. Additionally, each subscriber participant inthe set of subscriber participants has been assigned to a particular oneof the one or more video stream layers to be uploaded by the currentsender participant. A subscriber participant being assigned to aparticular video stream layer indicates that the subscriber participantwill receive that video stream layer having a particular bitrate fromthe current sender participant. For example, a first subscriberparticipant may be assigned to receive the 100 Kbps video stream layer,a second subscriber participant may be assigned to receive the 500 Kbpsvideo stream layer, a third subscriber participant may be assigned toreceive the 1 Mbps video stream layer, and a fourth subscriber may alsobe assigned to receive the 1 Mbps video stream layer. At lines 232-236,each subscriber participant's downlink capacity is updated bysubtracting the bitrate of the video stream layer to which thesubscriber participant has been assigned.

Each iteration of the first iterative sequence of lines 205-237 runs thesecond iterative sequence of lines 215-231 for a particular senderparticipant. It can be seen that once the second iterative sequence oflines 215-231 has been run for each sender participant, each senderparticipant will be assigned one or more video stream layers of varyingqualities that the sender participant is responsible for uploading, andeach subscriber participant will be assigned to a particular videostream layer from each sender participant to which the subscriberparticipant is subscribed.

Lines 223-229 implement an alternative embodiment which allows forpotential further optimization of sender participant uplink capacityusage. At line 224, a determination is made as to whether a currentsender participant's remaining uplink capacity is greater than or equalto a previous video stream layer's bitrate, and whether a currentsubscriber participant's reserved downlink is greater than or equal totwice the current sender participant's remaining uplink capacity. Ifboth of these conditions are satisfied, the previous video streamlayer's bitrate is added back into the current sender participant'sremaining uplink capacity (line 225). The previous video stream layer'sbitrate is modified so that the previous video stream layer's bitrate isequal to ¼ of the sender participant's remaining uplink capacity (line226), and a new video stream layer is created having a bitrate equal to¾ of the sender participant's remaining uplink capacity (lines 227-228).Essentially, these additional lines address a specific situation inwhich it may be desirable to decrease a previous video stream layer'sbitrate so as to be able to accommodate a second video stream layer thatis sufficiently distinct from the previous video stream layer.

FIG. 3 illustrates example pseudocode 300 for implementing variousfunctions of the bandwidth allocation module 106, according to anembodiment of the present disclosure. In particular, the pseudocode 300depicts one embodiment by which the bandwidth allocation module 106 candetermine a reserved downlink for a subscriber participant with respectto a particular sender participant. A subscriber participant's reserveddownlink can be determined based on the subscriber participant'sremaining downlink capacity. As described, a subscriber participant'sremaining downlink capacity is updated with each iteration of theiterative sequence implemented in lines 205-237 of pseudocode 200 ofFIG. 2. In a first iteration, the subscriber participant's remainingdownlink capacity is equal to their total downlink capacity. However,after the first iteration, a certain portion of the downlink capacitymay be assigned to receive a video stream layer from a first senderparticipant, and after a second iteration, a certain portion of thedownlink capacity may be assigned to receive a video stream layer from asecond sender participant, and so forth, such that a particularsubscriber participant's remaining downlink capacity will potentiallydecrease with each iteration. In various embodiments, a subscriberparticipant's reserved downlink can be determined based on thesubscriber participant's remaining downlink capacity at the time of thedetermination.

A subscriber participant's reserved downlink can also be determinedbased on a quality level of the subscriber participant's subscription toa particular sender participant. As described, a subscriberparticipant's subscription to a particular sender participant can beassociated with a particular quality level of a plurality of qualitylevels. For example, in one embodiment, there may be a low qualitylevel, a medium quality level, and a high quality level. In oneembodiment, a subscriber participant may specify which quality levelthey would like to receive from a particular sender participant. Inanother embodiment, a quality level may be inferred, for example, basedon a viewing mode selected by the subscriber participant.

In the example pseudocode 300, four quality levels are defined. Aquality level of 4 indicates a highest quality level, while a qualitylevel of 1 indicates a lowest quality level. If a subscriber participanthas requested a subscription having a quality level of 2 from a senderparticipant, the subscriber participant's reserved downlink iscalculated as the subscriber participant's remaining downlink capacitydivided by a number of sender participants yet to be processed for thesubscriber participant (lines 305-306). For example, consider an examplescenario in which the subscriber participant is subscribed to fourdifferent sender participants. Furthermore, the iterative sequence oflines 205-237 of FIG. 2 has gone through one iteration, such that one ofthe sender participants have been processed and the subscriberparticipant has been assigned to a particular video stream layer forthat sender participant, but the remaining three sender participantshave not yet been processed and the subscriber participant is not yetassigned to video stream layers for those sender participants. Thesubscriber participant's remaining downlink capacity has been updated toreflect the one video stream layer to which the subscriber participanthas been subscribed, and the number of sender participants yet to beprocessed for the subscriber participant is equal to three. As such, inthis example scenario, the subscriber participant's reserved downlinkwould be equal to his or her remaining downlink capacity divided bythree.

If a subscriber participant has requested a level 3 or a level 4subscription from a sender participant (i.e., a high qualitysubscription), the subscriber participant's reserved downlink iscalculated as the subscriber participant's remaining downlink capacitymultiplied by a high definition ratio (HD_RATIO). In the examplepseudocode 300, the high definition ratio is set to 0.5 (line 304), suchthat the reserved downlink is calculated as half of the subscriberparticipant's remaining downlink capacity. In various embodiments, theHD_RATIO may be a different value, and, as shown in the comment to line304, can vary based on, for example, the subscriber participant'sremaining subscriptions left to be processed.

If a subscriber participant has requested a level 1 subscription from asender participant, the subscriber participant's reserved downlink maydepend on the subscriber participant's remaining subscriptions. In theexample pseudocode 300, if the subscriber participant has a pending,unprocessed higher definition layer subscription (e.g., level 3 or level4), the reserved downlink is calculated as the subscriber participant'sremaining downlink capacity multiplied by one minus the HD_RATIO, andthe product is divided by the subscriber participant's remainingsubscriptions minus one (lines 311-312). In essence, this calculationreserves a portion of the subscriber participant's remaining downlinkcapacity for the pending higher definition layer subscription bycalculating the product of the remaining downlink capacity and one minusthe HD_RATIO, and then divides the left over downlink capacity by thenumber of pending subscriptions minus one. However, if the subscriberparticipant does not have a pending, unprocessed high definition layersubscription, the reserved downlink is calculated in the same way as thelevel 2/medium definition subscription (lines 313-315).

Additional clarity and explanation will now be provided with referenceto an example scenario.

FIG. 4A-4Q illustrate an example scenario 400 associated with groupvideo call simulcast optimization, according to an embodiment of thepresent disclosure. The example scenario 400 demonstrates variousfunctions of the group video call module 102, according to variousembodiments. As can be seen in FIG. 4A, the example scenario 400includes four users 402, 404, 406, and 408 that are participating in agroup video call. Each user is subscribed to every other user.Furthermore, the example scenario 400 includes three subscriptionquality levels, level 1 or “low definition” (LD), level 2 or “standarddefinition” (SD), and level 3 or “high definition” (HD).

User 402 has an uplink capacity of 200 kbps and a downlink capacity of200 kbps. User 402 has requested a standard definition video stream fromevery other user. This may be an instance, for example, in which theuser 402 has selected a “grid view” of the group video call such thatthe other participants are all displayed in individual windows ofsubstantially equal size.

User 404 has an uplink capacity of 300 kbps and a downlink capacity of200 kbps. User 404 has requested a low definition video stream fromusers 406 and 408, and a high definition video stream from user 402.This may be an instance, for example, in which the user 404 has the user402 on a full-screen view, and has users 406 and 408 displayed inthumbnail views.

User 406 has an uplink capacity of 350 kbps and a downlink capacity of600 kbps. Like user 402, user 406 has requested standard definitionvideo streams from every other user.

User 408 has an uplink capacity of 800 kbps and a downlink capacity of1000 kbps. Similar to user 404, user 408 has requested a low definitionvideo stream from users 404 and 406, and a high definition video streamfrom user 402.

As discussed above, in one embodiment, the set of users 402, 404, 406,408 can be ranked in ascending order based on uplink capacity, and theniteratively processed in sequence based on the ranking. In the examplescenario 400, the group video call is processed according to theembodiment implemented in pseudocode 200 of FIG. 2, with lines 223-229of pseudocode 200 being included.

In FIG. 4B, a first iteration of the iterative sequence implemented inlines 205-237 of FIG. 2 processes user 402, who has the lowest uplinkcapacity. In this first iteration, user 402 is the sender participant,and users 404, 406, and 408 are each subscriber participants that aresubscribed to user 402. In the example scenario 400, reserved downlinksare determined for each subscriber participant with respect to thesender participant according to the embodiment implemented in pseudocode300 of FIG. 3. As described, each subscriber participant's reserveddownlink is determined based on the subscriber participant's remainingdownlink capacity and a quality level associated with the subscriberparticipant's subscription to the sender participant. User 404 hasrequested a high definition video stream from the sender participant,i.e., user 402. As such, user 404's reserved downlink is calculated asuser 404's remaining downlink capacity (200 kbps) divided by 2 (asspecified in the HD_RATIO in line 304 of pseudocode 300). Therefore,user 404's reserved downlink is 100 Kbps. User 406 has requested astandard definition video stream from user 402. As such, user 406'sreserved downlink is calculated as user 406's remaining downlinkcapacity (600 kbps) divided by the number of user 406's subscriptionsremaining to be processed. In this first iteration, none of the senderparticipants have been processed, meaning user 406 still has threesubscriptions remaining to be processed. As such, user 406's reserveddownlink is 600 kbps/3=200 kbps. User 408 has requested a highdefinition video stream from user 402. As such, user 408's reserveddownlink is calculated as user 408's remaining downlink capacity (1000kbps) divided by 2, which is 500 Kbps.

FIG. 4C illustrates further processing of the subscriber participants.Per line 212 of FIG. 2, each subscriber participant is ranked inascending order based on reserved downlink. Per the second iterativesequence implemented in lines 215-236 of FIG. 2, each subscriberparticipant is processed sequentially based on the ranking. A firstiteration of the second iterative sequence processes user 404, who hasthe lowest reserved downlink. A first video stream layer having a sizeequal to user 404's reserved downlink (100 Kbps) is created, and user404 is assigned to the first video stream layer. Creation of the firstvideo stream layer having a bitrate of 100 Kbps indicates that thesender participant, user 402, will upload a first video stream layerhaving a bitrate of 100 Kbps. As such, user 402 has 100 Kbps of his orher uplink capacity dedicated to the first video stream layer, and 100Kbps of uplink capacity remaining. Assignment of the subscriberparticipant, user 404, to this first video stream layer indicates thatuser 404 will receive a 100 Kbps video stream layer from user 402. Asdescribed previously, while the present disclosure may state that asubscriber participant receives a video stream layer “from” a senderparticipant, it should be understood that, in various embodiments, thisreceipt is not a direct transmission of a video stream layer from oneparticipant to another. Rather, in various embodiments, a subscriberparticipant receives a video stream layer “from” a sender participant byvirtue of the sender participant uploading the video stream layer to acentral server, and the central server transmitting the video streamlayer to the subscriber participant based on the subscriber participantbeing assigned to receive that video stream layer.

A second iteration of the second iterative sequence processes user 406,who has the second lowest reserved downlink. Based on line 217 of FIG.2, a determination is made that there is insufficient remaining uplinkcapacity to create a new layer, since user 402's remaining uplinkcapacity (100 Kbps) is not two times greater than the previously createdvideo stream layer (100 Kbps). However, based on line 224 of FIG. 2, adetermination is made that user 402's remaining uplink capacity isgreater than or equal to the previously created video stream layer, anduser 406's reserved downlink is greater than or equal to twice user402's remaining uplink. In such a scenario, based on lines 224-229 ofFIG. 2, the previous video stream layer's bitrate is added back intouser 402's remaining uplink capacity (line 225), the previous videostream layer is redefined to have a bitrate equal to ¼ of the remaininguplink capacity (line 226), and a new video stream layer is created witha bitrate equal to ¾ of the remaining uplink capacity (line 228). Assuch, the first video stream layer is redefined to have a bitrate of 50kbps rather than 100 Kbps, and a new, second video stream layer iscreated having a bitrate of 150 kbps. User 404 remains assigned to thefirst video stream layer, which is now a 50 kbps video stream, and user406 is assigned to the newly created second video stream layer, which isa 150 kbps video stream. User 402 is now assigned to upload a 50 kbpsvideo stream layer and a 150 kbps video stream layer, which completelyutilizes user 402's uplink capacity.

A third iteration of the second iterative sequence processes user 408,who has the third lowest reserved downlink. There is insufficient uplinkcapacity remaining for user 402 to create a new video stream layer. Assuch, user 408 is assigned to the previous video stream layer, i.e., the150 kbps video stream layer.

FIG. 4D summarizes the results of the first iteration of the iterativesequence of lines 205-237 of FIG. 2. User 402 has been assigned toupload two video stream layers, a first video stream layer having abitrate of 50 kbps and a second video stream layer having a bitrate of150 kbps. User 402's uplink capacity is updated by subtracting thebitrates of the two video stream layers that user 402 will upload,resulting in a remaining uplink capacity of 0 kbps.

User 404 is assigned to receive the first video stream layer from user402, and users 406 and 408 are both assigned to receive the second videostream layer from user 402. User 404's downlink capacity is updated bysubtracting 50 kbps, user 406's downlink capacity is updated bysubtracting 150 kbps, and user 408's downlink capacity is updated bysubtracting 150 kbps. FIG. 4E presents the status of the participantsafter the first iteration of the iterative sequence of lines 205-237 ofFIG. 2.

FIG. 4F illustrates the start of a second iteration of the iterativesequence of lines 205-237 of FIG. 2. In this second iteration, user 404is selected as the sender participant being processed, as user 404 hasthe second lowest uplink capacity of the four users, and users 402, 406,and 408 are each subscriber participants that are subscribed to user404. Once again, reserved downlinks are determined for each subscriberparticipant with respect to the sender participant, according to theembodiment implemented in pseudocode 300 of FIG. 3. User 402 hasrequested a standard definition video stream from the senderparticipant, i.e., user 404. As such, user 402's reserved downlink iscalculated as user 402's remaining downlink capacity (200 kbps) dividedby the number of user 402's subscriptions remaining to be processed.User 402 still has three subscriptions remaining to be processed (users404, 406, and 408), so user 402's reserved downlink is 200 kbps/3=66kbps. User 406 has also requested a standard definition video streamfrom user 404. As such, user 406's reserved downlink is calculated asuser 406's remaining downlink capacity (450 kbps) divided by the numberof user 406's subscriptions remaining to be processed. One of user 406'ssubscriptions has already been processed (user 402), so user 406 hasonly two subscriptions remaining to be processed (users 404 and 408). Assuch, user 406's reserved downlink is 450 kbps/2=225 kbps. User 408 hasrequested a low definition video stream from user 402 (as addressed bylines 309-315 of FIG. 3). User 408 does not have a high definitionsubscription remaining to be processed. Therefore, user 408's reserveddownlink is equal to user 408's remaining downlink capacity divided bythe number of user 408's subscriptions remaining to be processed. User408 has two subscriptions remaining to be processed (users 404 and 406).Therefore, user 408's reserved downlink is 850 kbps/2=425 kbps.

FIG. 4G illustrates further processing of the subscriber participants.Per line 212 of FIG. 2, each subscriber participant is ranked inascending order based on reserved downlink. Per the second iterativesequence implemented in lines 215-236 of FIG. 2, each subscriberparticipant is processed sequentially based on the ranking. A firstiteration of the second iterative sequence processes user 402, who hasthe lowest reserved downlink. A first video stream layer having a sizeequal to user 402's reserved downlink (66 kbps) is created, and user 402is assigned to the first video stream layer. Creation of the first videostream layer having a bitrate of 66 kbps indicates that the senderparticipant, user 404, will upload a first video stream layer having abitrate of 66 kbps. As such, user 404 has 66 kbps of his or her uplinkcapacity dedicated to the first video stream layer, and 234 kbps ofuplink capacity remaining.

A second iteration of the second iterative sequence processes user 406,who has the second lowest reserved downlink. A determination is madethat user 406's reserved downlink (which is less than user 404'sremaining uplink capacity) is at least twice the previously createdvideo stream layer. As such, a new second video stream layer having asize equal to user 406's reserved downlink (225 kbps) is created. User404 is now tasked with uploading two video streams, a first that is 66kbps and a second that is 225 kbps, which means that user 404 has 9 kbpsof uplink capacity remaining. User 406 is assigned to the second videostream layer.

A third iteration of the second iterative sequence processes user 408,who has the third lowest reserved downlink. There is insufficient uplinkcapacity remaining for user 404 to create a new video stream layer. Assuch, user 408 is assigned to the previous video stream layer, i.e., the225 kbps video stream layer.

FIG. 4H summarizes the results of the second iteration of the iterativesequence of lines 205-237 of FIG. 2. User 404 has been assigned toupload two video stream layers, a first video stream layer having abitrate of 66 kbps and a second video stream layer having a bitrate of225 kbps. User 404's uplink capacity is updated by subtracting thebitrates of the two video stream layers that user 404 will upload,resulting in a remaining uplink capacity of 9 kbps. User 402 is assignedto receive the first video stream layer from user 404, and users 406 and408 are both assigned to receive the second video stream layer from user404. User 402's downlink capacity is updated by subtracting 66 kbps,user 406's downlink capacity is updated by subtracting 225 kbps, anduser 408's downlink capacity is updated by subtracting 225 kbps. FIG. 4Ipresents the status of the participants after the second iteration ofthe iterative sequence of lines 205-237 of FIG. 2.

FIG. 4J illustrates the start of a third iteration of the iterativesequence of lines 205-237 of FIG. 2. In this third iteration, user 406is selected as the sender participant being processed, as user 406 hasthe third lowest uplink capacity of the four users, and users 402, 404,and 408 are each subscriber participants that are subscribed to user406. Once again, reserved downlinks are determined for each subscriberparticipant with respect to the sender participant, which is user 406 inthis iteration, according to the embodiment implemented in pseudocode300 of FIG. 3. User 402 has requested a standard definition video streamfrom the sender participant, i.e., user 406. As such, user 402'sreserved downlink is calculated as user 402's remaining downlinkcapacity (134 kbps) divided by the number of user 402's subscriptionsremaining to be processed. User 402 now has two subscriptions remainingto be processed (users 406 and 408), so user 402's reserved downlink is134 kbps/2=67 kbps. User 404 has requested a low definition video streamfrom user 406. User 404 does not have any high definition subscriptionsremaining to be processed. As such, user 404's reserved downlink iscalculated as user 404's remaining downlink capacity (150 kbps) dividedby the number of user 404's subscriptions remaining to be processed.User 404 has two subscriptions remaining to be processed (users 406 and408). As such, user 404's reserved downlink is 150 kbps/2=75 kbps. User408 has requested a low definition video stream from user 406. User 408does not have a high definition subscription remaining to be processed.Therefore, user 408's reserved downlink is equal to user 408's remainingdownlink capacity divided by the number of user 408's subscriptionsremaining to be processed. User 408 has only one subscription remainingto be processed (user 406). Therefore, user 408's reserved downlink is625 kbps/1=625 kbps.

FIG. 4K illustrates further processing of the subscriber participants.Per line 212 of FIG. 2, each subscriber participant is ranked inascending order based on reserved downlink. Per the second iterativesequence implemented in lines 215-236 of FIG. 2, each subscriberparticipant is processed sequentially based on the ranking. A firstiteration of the second iterative sequence processes user 402, who hasthe lowest reserved downlink. A first video stream layer having a sizeequal to user 402's reserved downlink (67 kbps) is created, and user 402is assigned to the first video stream layer. This indicates that thesender participant, user 406, will upload a first video stream layerhaving a bitrate of 67 kbps. As such, user 406 has 67 kbps of his or heruplink capacity dedicated to the first video stream layer, and 283 kbpsof uplink capacity remaining.

A second iteration of the second iterative sequence processes user 404,who has the second lowest reserved downlink. A determination is madethat user 404's reserved downlink does not satisfy the differencethreshold with respect to the previous video stream layer, i.e., is notat least twice the bitrate of the previous video stream layer. As such,user 404 is assigned to the previously created first video stream layerhaving a bitrate of 67 kbps.

A third iteration of the second iterative sequence processes user 408,who has the third lowest reserved downlink. User 406's remaining uplinkcapacity is less than user 408's reserved downlink. As such, the size ofa potential new layer is set equal to user 406's remaining uplinkcapacity, i.e., 283 kbps. The size of the potential new layer satisfiesthe difference threshold, i.e., is at least twice the bitrate of theprevious video stream layer. Therefore, a new, second video stream layeris created having a bitrate of 283 kbps. User 408 is assigned to thesecond video stream layer.

FIG. 4L summarizes the results of the third iteration of the iterativesequence of lines 205-237 of FIG. 2. User 406 has been assigned toupload two video stream layers, a first video stream layer having abitrate of 67 kbps and a second video stream layer having a bitrate of283 kbps. User 406's uplink capacity is updated by subtracting thebitrates of the two video stream layers that user 406 will upload,resulting in a remaining uplink capacity of 0 kbps. Users 402 and 404are both assigned to receive the first video stream layer from user 406,and user 408 is assigned to receive the second video stream layer fromuser 406. User 402's downlink capacity is updated by subtracting 67kbps, user 404's downlink capacity is updated by subtracting 67 kbps,and user 408's downlink capacity is updated by subtracting 283 kbps.FIG. 4M presents the status of the participants after the thirditeration of the iterative sequence of lines 205-237 of FIG. 2.

FIG. 4N illustrates the start of a fourth and final iteration of theiterative sequence of lines 205-237 of FIG. 2. In this fourth iteration,user 408 is selected as the sender participant being processed, andusers 402, 404, and 406 are each subscriber participants that aresubscribed to user 408. Once again, reserved downlinks are determinedfor each subscriber participant with respect to the sender participantaccording to the embodiment implemented in pseudocode 300 of FIG. 3.User 402 has requested a standard definition video stream from thesender participant, i.e., user 408. As such, user 402's reserveddownlink is calculated as user 402's remaining downlink capacity (67kbps) divided by the number of user 402's subscriptions remaining to beprocessed. User 402 now has only one subscription remaining to beprocessed (user 408), so user 402's reserved downlink is 67 kbps/1=67kbps. User 404 has requested a low definition video stream from user408. User 404 does not have any high definition subscriptions remainingto be processed. As such, user 404's reserved downlink is calculated asuser 404's remaining downlink capacity (83 kbps) divided by the numberof user 404's subscriptions remaining to be processed. User 404 has onlyone subscription remaining to be processed (user 408). As such, user404's reserved downlink is 83 kbps/1=83 kbps. User 406 has requested astandard definition video stream from user 408. Therefore, user 406'sreserved downlink is equal to user 406's remaining downlink capacitydivided by the number of user 406's subscriptions remaining to beprocessed. User 406 has only one subscription remaining to be processed(user 408). Therefore, user 406's reserved downlink is 225 kbps/1=225kbps.

FIG. 4O illustrates further processing of the subscriber participants.Per line 212 of FIG. 2, each subscriber participant is ranked inascending order based on reserved downlink. Per the second iterativesequence implemented in lines 215-236 of FIG. 2, each subscriberparticipant is processed sequentially based on the ranking. A firstiteration of the second iterative sequence processes user 402, who hasthe lowest reserved downlink. A first video stream layer having a sizeequal to user 402's reserved downlink (67 kbps) is created, and user 402is assigned to the first video stream layer. User 408 has 67 kbps of hisor her uplink capacity dedicated to the first video stream layer, and733 kbps of uplink capacity remaining.

A second iteration of the second iterative sequence processes user 404,who has the second lowest reserved downlink. A determination is madethat user 404's reserved downlink does not satisfy the differencethreshold with respect to the previous video stream layer, i.e., is notat least twice the bitrate of the previous video stream layer. As such,user 404 is assigned to the previously created first video stream layerof 67 kbps.

A third iteration of the second iterative sequence processes user 406,who has the third lowest reserved downlink. User 406's reserved downlink(225 kbps) is less than user 408's remaining uplink capacity (733 kbps).As such, the size of a potential new layer is set equal to user 406'sreserved downlink, i.e., 225 kbps. The size of the potential new layersatisfies the difference threshold, i.e., is at least twice the bitrateof the previous video stream layer. Therefore, a new second video streamlayer is created having a bitrate of 225 kbps. User 406 is assigned tothe second video stream layer.

FIG. 4P summarizes the results of the fourth iteration of the iterativesequence of lines 205-237 of FIG. 2. User 408 has been assigned toupload two video stream layers, a first video stream layer having abitrate of 67 kbps and a second video stream layer having a bitrate of225 kbps. User 408's uplink capacity is updated by subtracting thebitrates of the two video stream layers that user 408 will upload,resulting in a remaining uplink capacity of 508 kbps. Users 402 and 404are both assigned to receive the first video stream layer from user 408,and user 406 is assigned to receive the second video stream layer fromuser 408. User 402's downlink capacity is updated by subtracting 67kbps, user 404's downlink capacity is updated by subtracting 67 kbps,and user 406's downlink capacity is updated by subtracting 225 kbps.FIG. 4Q presents the status of the participants after the fourth andfinal iteration of the iterative sequence of lines 205-237 of FIG. 2. Ascan be seen, each sender participant (in this case, each participant)has been assigned one or more video stream layers that the participantwill upload, and each subscriber participant (in this case, eachparticipant) has been assigned to receive one video stream having aparticular bitrate from each sender participant that the subscriberparticipant is subscribed to.

While the example scenario described above describes an example scenarioin which every participant in the group video call is both a senderparticipant and a subscriber participant, it should be appreciated thatthe present disclosure is capable of processing and managing group videocalls having differing characteristics. For example, a subset ofparticipants may be sender participants, such that only someparticipants are uploading video streams, and/or a subset ofparticipants may be subscriber participants, such that only someparticipants are receiving video streams from other participants.Similarly, while the example scenario described above described anexample scenario in which every participant receives a video stream fromevery other participant, it should be appreciated that the presentdisclosure can address differing scenarios. For example, certainsubscriber participants may only be subscribed to receive video feedsfrom a subset of sender participants. Many variations are possible.

The example embodiments described above have generally attempted toutilize as much of a sender participant's uplink capacity and as much ofa subscriber participant's downlink capacity as possible. However, incertain scenarios, it may be desirable to impose limits or caps onbitrates even if additional uplink capacity and/or downlink capacity isavailable. For example, if a subscriber participant has requested a lowdefinition video stream from a sender participant, it may be desirableto cap the bitrate of the low definition video stream even if thesubscriber participant has sufficient downlink capacity and the senderparticipant has sufficient uplink capacity to accommodate a very highbitrate video stream. As such, in various embodiments, subscriptions ofparticular quality levels may be capped at a maximum bitrate. Forexample, a low quality subscription may be capped at a first maximumbitrate, while a standard or medium quality subscription may be cappedat a second maximum bitrate that is greater than the first maximumbitrate, while a high quality subscription may be capped at a thirdmaximum bitrate that is greater than the second maximum bitrate, or, invarious embodiments, may not be capped at all.

FIG. 5 illustrates an example method 500 associated with optimizinggroup video call simulcast streams, according to an embodiment of thepresent disclosure. It should be appreciated that there can beadditional, fewer, or alternative steps performed in similar oralternative orders, or in parallel, within the scope of the variousembodiments discussed herein unless otherwise stated.

At block 502, the example method 500 can identify a set of participantsin a group video call, wherein each participant is associated with anuplink capacity and a downlink capacity, and the set of participantsincludes a set of sender participants and a set of subscriberparticipants. At block 504, the example method 500 can, for each senderparticipant of the set of sender participants, determine one or morevideo stream layers to be uploaded by the sender participant based ondownlink capacities of subscriber participants subscribed to the senderparticipant. At block 506, the example method 500 can, for eachsubscriber participant of the set of subscriber participants, assign thesubscriber participant to receive one video stream layer of the one ormore video stream layers to be uploaded by each sender participant towhich the subscriber participant is subscribed.

It is contemplated that there can be many other uses, applications,and/or variations associated with the various embodiments of the presentdisclosure. For example, in some cases, user can choose whether or notto opt-in to utilize the disclosed technology. The disclosed technologycan also ensure that various privacy settings and preferences aremaintained and can prevent private information from being divulged. Inanother example, various embodiments of the present disclosure canlearn, improve, and/or be refined over time.

Social Networking System—Example Implementation

FIG. 6 illustrates a network diagram of an example system 600 that canbe utilized in various scenarios, according to an embodiment of thepresent disclosure. The system 600 includes one or more user devices610, one or more external systems 620, a social networking system (orservice) 630, and a network 650. In an embodiment, the social networkingservice, provider, and/or system discussed in connection with theembodiments described above may be implemented as the social networkingsystem 630. For purposes of illustration, the embodiment of the system600, shown by FIG. 6, includes a single external system 620 and a singleuser device 610. However, in other embodiments, the system 600 mayinclude more user devices 610 and/or more external systems 620. Incertain embodiments, the social networking system 630 is operated by asocial network provider, whereas the external systems 620 are separatefrom the social networking system 630 in that they may be operated bydifferent entities. In various embodiments, however, the socialnetworking system 630 and the external systems 620 operate inconjunction to provide social networking services to users (or members)of the social networking system 630. In this sense, the socialnetworking system 630 provides a platform or backbone, which othersystems, such as external systems 620, may use to provide socialnetworking services and functionalities to users across the Internet.

The user device 610 comprises one or more computing devices that canreceive input from a user and transmit and receive data via the network650. In one embodiment, the user device 610 is a conventional computersystem executing, for example, a Microsoft Windows compatible operatingsystem (OS), Apple OS X, and/or a Linux distribution. In anotherembodiment, the user device 610 can be a device having computerfunctionality, such as a smart-phone, a tablet, a personal digitalassistant (PDA), a mobile telephone, etc. The user device 610 isconfigured to communicate via the network 650. The user device 610 canexecute an application, for example, a browser application that allows auser of the user device 610 to interact with the social networkingsystem 630. In another embodiment, the user device 610 interacts withthe social networking system 630 through an application programminginterface (API) provided by the native operating system of the userdevice 610, such as iOS and ANDROID. The user device 610 is configuredto communicate with the external system 620 and the social networkingsystem 630 via the network 650, which may comprise any combination oflocal area and/or wide area networks, using wired and/or wirelesscommunication systems.

In one embodiment, the network 650 uses standard communicationstechnologies and protocols. Thus, the network 650 can include linksusing technologies such as Ethernet, 802.11, worldwide interoperabilityfor microwave access (WiMAX), 3G, 4G, CDMA, GSM, LTE, digital subscriberline (DSL), etc. Similarly, the networking protocols used on the network650 can include multiprotocol label switching (MPLS), transmissioncontrol protocol/Internet protocol (TCP/IP), User Datagram Protocol(UDP), hypertext transport protocol (HTTP), simple mail transferprotocol (SMTP), file transfer protocol (FTP), and the like. The dataexchanged over the network 650 can be represented using technologiesand/or formats including hypertext markup language (HTML) and extensiblemarkup language (XML). In addition, all or some links can be encryptedusing conventional encryption technologies such as secure sockets layer(SSL), transport layer security (TLS), and Internet Protocol security(IPsec).

In one embodiment, the user device 610 may display content from theexternal system 620 and/or from the social networking system 630 byprocessing a markup language document 614 received from the externalsystem 620 and from the social networking system 630 using a browserapplication 612. The markup language document 614 identifies content andone or more instructions describing formatting or presentation of thecontent. By executing the instructions included in the markup languagedocument 614, the browser application 612 displays the identifiedcontent using the format or presentation described by the markuplanguage document 614. For example, the markup language document 614includes instructions for generating and displaying a web page havingmultiple frames that include text and/or image data retrieved from theexternal system 620 and the social networking system 630. In variousembodiments, the markup language document 614 comprises a data fileincluding extensible markup language (XML) data, extensible hypertextmarkup language (XHTML) data, or other markup language data.Additionally, the markup language document 614 may include JavaScriptObject Notation (JSON) data, JSON with padding (JSONP), and JavaScriptdata to facilitate data-interchange between the external system 620 andthe user device 610. The browser application 612 on the user device 610may use a JavaScript compiler to decode the markup language document614.

The markup language document 614 may also include, or link to,applications or application frameworks such as FLASH™ or Unity™applications, the SilverLight™ application framework, etc.

In one embodiment, the user device 610 also includes one or more cookies616 including data indicating whether a user of the user device 610 islogged into the social networking system 630, which may enablemodification of the data communicated from the social networking system630 to the user device 610.

The external system 620 includes one or more web servers that includeone or more web pages 622 a, 622 b, which are communicated to the userdevice 610 using the network 650. The external system 620 is separatefrom the social networking system 630. For example, the external system620 is associated with a first domain, while the social networkingsystem 630 is associated with a separate social networking domain. Webpages 622 a, 622 b, included in the external system 620, comprise markuplanguage documents 614 identifying content and including instructionsspecifying formatting or presentation of the identified content.

The social networking system 630 includes one or more computing devicesfor a social network, including a plurality of users, and providingusers of the social network with the ability to communicate and interactwith other users of the social network. In some instances, the socialnetwork can be represented by a graph, i.e., a data structure includingedges and nodes. Other data structures can also be used to represent thesocial network, including but not limited to databases, objects,classes, meta elements, files, or any other data structure. The socialnetworking system 630 may be administered, managed, or controlled by anoperator. The operator of the social networking system 630 may be ahuman being, an automated application, or a series of applications formanaging content, regulating policies, and collecting usage metricswithin the social networking system 630. Any type of operator may beused.

Users may join the social networking system 630 and then add connectionsto any number of other users of the social networking system 630 to whomthey desire to be connected. As used herein, the term “friend” refers toany other user of the social networking system 630 to whom a user hasformed a connection, association, or relationship via the socialnetworking system 630. For example, in an embodiment, if users in thesocial networking system 630 are represented as nodes in the socialgraph, the term “friend” can refer to an edge formed between anddirectly connecting two user nodes.

Connections may be added explicitly by a user or may be automaticallycreated by the social networking system 630 based on commoncharacteristics of the users (e.g., users who are alumni of the sameeducational institution). For example, a first user specifically selectsa particular other user to be a friend. Connections in the socialnetworking system 630 are usually in both directions, but need not be,so the terms “user” and “friend” depend on the frame of reference.Connections between users of the social networking system 630 areusually bilateral (“two-way”), or “mutual,” but connections may also beunilateral, or “one-way.” For example, if Bob and Joe are both users ofthe social networking system 630 and connected to each other, Bob andJoe are each other's connections. If, on the other hand, Bob wishes toconnect to Joe to view data communicated to the social networking system630 by Joe, but Joe does not wish to form a mutual connection, aunilateral connection may be established. The connection between usersmay be a direct connection; however, some embodiments of the socialnetworking system 630 allow the connection to be indirect via one ormore levels of connections or degrees of separation.

In addition to establishing and maintaining connections between usersand allowing interactions between users, the social networking system630 provides users with the ability to take actions on various types ofitems supported by the social networking system 630. These items mayinclude groups or networks (i.e., social networks of people, entities,and concepts) to which users of the social networking system 630 maybelong, events or calendar entries in which a user might be interested,computer-based applications that a user may use via the socialnetworking system 630, transactions that allow users to buy or sellitems via services provided by or through the social networking system630, and interactions with advertisements that a user may perform on oroff the social networking system 630. These are just a few examples ofthe items upon which a user may act on the social networking system 630,and many others are possible. A user may interact with anything that iscapable of being represented in the social networking system 630 or inthe external system 620, separate from the social networking system 630,or coupled to the social networking system 630 via the network 650.

The social networking system 630 is also capable of linking a variety ofentities. For example, the social networking system 630 enables users tointeract with each other as well as external systems 620 or otherentities through an API, a web service, or other communication channels.The social networking system 630 generates and maintains the “socialgraph” comprising a plurality of nodes interconnected by a plurality ofedges. Each node in the social graph may represent an entity that canact on another node and/or that can be acted on by another node. Thesocial graph may include various types of nodes. Examples of types ofnodes include users, non-person entities, content items, web pages,groups, activities, messages, concepts, and any other things that can berepresented by an object in the social networking system 630. An edgebetween two nodes in the social graph may represent a particular kind ofconnection, or association, between the two nodes, which may result fromnode relationships or from an action that was performed by one of thenodes on the other node. In some cases, the edges between nodes can beweighted. The weight of an edge can represent an attribute associatedwith the edge, such as a strength of the connection or associationbetween nodes. Different types of edges can be provided with differentweights. For example, an edge created when one user “likes” another usermay be given one weight, while an edge created when a user befriendsanother user may be given a different weight.

As an example, when a first user identifies a second user as a friend,an edge in the social graph is generated connecting a node representingthe first user and a second node representing the second user. Asvarious nodes relate or interact with each other, the social networkingsystem 630 modifies edges connecting the various nodes to reflect therelationships and interactions.

The social networking system 630 also includes user-generated content,which enhances a user's interactions with the social networking system630. User-generated content may include anything a user can add, upload,send, or “post” to the social networking system 630. For example, a usercommunicates posts to the social networking system 630 from a userdevice 610. Posts may include data such as status updates or othertextual data, location information, images such as photos, videos,links, music or other similar data and/or media. Content may also beadded to the social networking system 630 by a third party. Content“items” are represented as objects in the social networking system 630.In this way, users of the social networking system 630 are encouraged tocommunicate with each other by posting text and content items of varioustypes of media through various communication channels. Suchcommunication increases the interaction of users with each other andincreases the frequency with which users interact with the socialnetworking system 630.

The social networking system 630 includes a web server 632, an APIrequest server 634, a user profile store 636, a connection store 638, anaction logger 640, an activity log 642, and an authorization server 644.In an embodiment of the invention, the social networking system 630 mayinclude additional, fewer, or different components for variousapplications. Other components, such as network interfaces, securitymechanisms, load balancers, failover servers, management and networkoperations consoles, and the like are not shown so as to not obscure thedetails of the system.

The user profile store 636 maintains information about user accounts,including biographic, demographic, and other types of descriptiveinformation, such as work experience, educational history, hobbies orpreferences, location, and the like that has been declared by users orinferred by the social networking system 630. This information is storedin the user profile store 636 such that each user is uniquelyidentified. The social networking system 630 also stores data describingone or more connections between different users in the connection store638. The connection information may indicate users who have similar orcommon work experience, group memberships, hobbies, or educationalhistory. Additionally, the social networking system 630 includesuser-defined connections between different users, allowing users tospecify their relationships with other users. For example, user-definedconnections allow users to generate relationships with other users thatparallel the users' real-life relationships, such as friends,co-workers, partners, and so forth. Users may select from predefinedtypes of connections, or define their own connection types as needed.Connections with other nodes in the social networking system 630, suchas non-person entities, buckets, cluster centers, images, interests,pages, external systems, concepts, and the like are also stored in theconnection store 638.

The social networking system 630 maintains data about objects with whicha user may interact. To maintain this data, the user profile store 636and the connection store 638 store instances of the corresponding typeof objects maintained by the social networking system 630. Each objecttype has information fields that are suitable for storing informationappropriate to the type of object. For example, the user profile store636 contains data structures with fields suitable for describing auser's account and information related to a user's account. When a newobject of a particular type is created, the social networking system 630initializes a new data structure of the corresponding type, assigns aunique object identifier to it, and begins to add data to the object asneeded. This might occur, for example, when a user becomes a user of thesocial networking system 630, the social networking system 630 generatesa new instance of a user profile in the user profile store 636, assignsa unique identifier to the user account, and begins to populate thefields of the user account with information provided by the user.

The connection store 638 includes data structures suitable fordescribing a user's connections to other users, connections to externalsystems 620 or connections to other entities. The connection store 638may also associate a connection type with a user's connections, whichmay be used in conjunction with the user's privacy setting to regulateaccess to information about the user. In an embodiment of the invention,the user profile store 636 and the connection store 638 may beimplemented as a federated database.

Data stored in the connection store 638, the user profile store 636, andthe activity log 642 enables the social networking system 630 togenerate the social graph that uses nodes to identify various objectsand edges connecting nodes to identify relationships between differentobjects. For example, if a first user establishes a connection with asecond user in the social networking system 630, user accounts of thefirst user and the second user from the user profile store 636 may actas nodes in the social graph. The connection between the first user andthe second user stored by the connection store 638 is an edge betweenthe nodes associated with the first user and the second user. Continuingthis example, the second user may then send the first user a messagewithin the social networking system 630. The action of sending themessage, which may be stored, is another edge between the two nodes inthe social graph representing the first user and the second user.Additionally, the message itself may be identified and included in thesocial graph as another node connected to the nodes representing thefirst user and the second user.

In another example, a first user may tag a second user in an image thatis maintained by the social networking system 630 (or, alternatively, inan image maintained by another system outside of the social networkingsystem 630). The image may itself be represented as a node in the socialnetworking system 630. This tagging action may create edges between thefirst user and the second user as well as create an edge between each ofthe users and the image, which is also a node in the social graph. Inyet another example, if a user confirms attending an event, the user andthe event are nodes obtained from the user profile store 636, where theattendance of the event is an edge between the nodes that may beretrieved from the activity log 642. By generating and maintaining thesocial graph, the social networking system 630 includes data describingmany different types of objects and the interactions and connectionsamong those objects, providing a rich source of socially relevantinformation.

The web server 632 links the social networking system 630 to one or moreuser devices 610 and/or one or more external systems 620 via the network650. The web server 632 serves web pages, as well as other web-relatedcontent, such as Java, JavaScript, Flash, XML, and so forth. The webserver 632 may include a mail server or other messaging functionalityfor receiving and routing messages between the social networking system630 and one or more user devices 610. The messages can be instantmessages, queued messages (e.g., email), text and SMS messages, or anyother suitable messaging format.

The API request server 634 allows one or more external systems 620 anduser devices 610 to call access information from the social networkingsystem 630 by calling one or more API functions. The API request server634 may also allow external systems 620 to send information to thesocial networking system 630 by calling APIs. The external system 620,in one embodiment, sends an API request to the social networking system630 via the network 650, and the API request server 634 receives the APIrequest. The API request server 634 processes the request by calling anAPI associated with the API request to generate an appropriate response,which the API request server 634 communicates to the external system 620via the network 650. For example, responsive to an API request, the APIrequest server 634 collects data associated with a user, such as theuser's connections that have logged into the external system 620, andcommunicates the collected data to the external system 620. In anotherembodiment, the user device 610 communicates with the social networkingsystem 630 via APIs in the same manner as external systems 620.

The action logger 640 is capable of receiving communications from theweb server 632 about user actions on and/or off the social networkingsystem 630. The action logger 640 populates the activity log 642 withinformation about user actions, enabling the social networking system630 to discover various actions taken by its users within the socialnetworking system 630 and outside of the social networking system 630.Any action that a particular user takes with respect to another node onthe social networking system 630 may be associated with each user'saccount, through information maintained in the activity log 642 or in asimilar database or other data repository. Examples of actions taken bya user within the social networking system 630 that are identified andstored may include, for example, adding a connection to another user,sending a message to another user, reading a message from another user,viewing content associated with another user, attending an event postedby another user, posting an image, attempting to post an image, or otheractions interacting with another user or another object. When a usertakes an action within the social networking system 630, the action isrecorded in the activity log 642. In one embodiment, the socialnetworking system 630 maintains the activity log 642 as a database ofentries. When an action is taken within the social networking system630, an entry for the action is added to the activity log 642. Theactivity log 642 may be referred to as an action log.

Additionally, user actions may be associated with concepts and actionsthat occur within an entity outside of the social networking system 630,such as an external system 620 that is separate from the socialnetworking system 630. For example, the action logger 640 may receivedata describing a user's interaction with an external system 620 fromthe web server 632. In this example, the external system 620 reports auser's interaction according to structured actions and objects in thesocial graph.

Other examples of actions where a user interacts with an external system620 include a user expressing an interest in an external system 620 oranother entity, a user posting a comment to the social networking system630 that discusses an external system 620 or a web page 622 a within theexternal system 620, a user posting to the social networking system 630a Uniform Resource Locator (URL) or other identifier associated with anexternal system 620, a user attending an event associated with anexternal system 620, or any other action by a user that is related to anexternal system 620. Thus, the activity log 642 may include actionsdescribing interactions between a user of the social networking system630 and an external system 620 that is separate from the socialnetworking system 630.

The authorization server 644 enforces one or more privacy settings ofthe users of the social networking system 630. A privacy setting of auser determines how particular information associated with a user can beshared. The privacy setting comprises the specification of particularinformation associated with a user and the specification of the entityor entities with whom the information can be shared. Examples ofentities with which information can be shared may include other users,applications, external systems 620, or any entity that can potentiallyaccess the information. The information that can be shared by a usercomprises user account information, such as profile photos, phonenumbers associated with the user, user's connections, actions taken bythe user such as adding a connection, changing user profile information,and the like.

The privacy setting specification may be provided at different levels ofgranularity. For example, the privacy setting may identify specificinformation to be shared with other users; the privacy settingidentifies a work phone number or a specific set of related information,such as, personal information including profile photo, home phonenumber, and status. Alternatively, the privacy setting may apply to allthe information associated with the user. The specification of the setof entities that can access particular information can also be specifiedat various levels of granularity. Various sets of entities with whichinformation can be shared may include, for example, all friends of theuser, all friends of friends, all applications, or all external systems620. One embodiment allows the specification of the set of entities tocomprise an enumeration of entities. For example, the user may provide alist of external systems 620 that are allowed to access certaininformation. Another embodiment allows the specification to comprise aset of entities along with exceptions that are not allowed to access theinformation. For example, a user may allow all external systems 620 toaccess the user's work information, but specify a list of externalsystems 620 that are not allowed to access the work information. Certainembodiments call the list of exceptions that are not allowed to accesscertain information a “block list”. External systems 620 belonging to ablock list specified by a user are blocked from accessing theinformation specified in the privacy setting. Various combinations ofgranularity of specification of information, and granularity ofspecification of entities, with which information is shared arepossible. For example, all personal information may be shared withfriends whereas all work information may be shared with friends offriends.

The authorization server 644 contains logic to determine if certaininformation associated with a user can be accessed by a user's friends,external systems 620, and/or other applications and entities. Theexternal system 620 may need authorization from the authorization server644 to access the user's more private and sensitive information, such asthe user's work phone number. Based on the user's privacy settings, theauthorization server 644 determines if another user, the external system620, an application, or another entity is allowed to access informationassociated with the user, including information about actions taken bythe user.

In some embodiments, the social networking system 630 can include agroup video call module 646. The group video call module 646 can, forexample, be implemented as the group video call module 102, as discussedin more detail herein. As discussed previously, it should be appreciatedthat there can be many variations or other possibilities. For example,in some embodiments, one or more functionalities of the group video callmodule 646 can be implemented in the user device 610. As discussedpreviously, it should be appreciated that there can be many variationsor other possibilities.

Hardware Implementation

The foregoing processes and features can be implemented by a widevariety of machine and computer system architectures and in a widevariety of network and computing environments. FIG. 7 illustrates anexample of a computer system 700 that may be used to implement one ormore of the embodiments described herein according to an embodiment ofthe invention. The computer system 700 includes sets of instructions forcausing the computer system 700 to perform the processes and featuresdiscussed herein. The computer system 700 may be connected (e.g.,networked) to other machines. In a networked deployment, the computersystem 700 may operate in the capacity of a server machine or a clientmachine in a client-server network environment, or as a peer machine ina peer-to-peer (or distributed) network environment. In an embodiment ofthe invention, the computer system 700 may be the social networkingsystem 630, the user device 610, and the external system 620, or acomponent thereof. In an embodiment of the invention, the computersystem 700 may be one server among many that constitutes all or part ofthe social networking system 630.

The computer system 700 includes a processor 702, a cache 704, and oneor more executable modules and drivers, stored on a computer-readablemedium, directed to the processes and features described herein.Additionally, the computer system 700 includes a high performanceinput/output (I/O) bus 706 and a standard I/O bus 708. A host bridge 710couples processor 702 to high performance I/O bus 706, whereas I/O busbridge 712 couples the two buses 706 and 708 to each other. A systemmemory 714 and one or more network interfaces 716 couple to highperformance I/O bus 706. The computer system 700 may further includevideo memory and a display device coupled to the video memory (notshown). Mass storage 718 and I/O ports 720 couple to the standard I/Obus 708. The computer system 700 may optionally include a keyboard andpointing device, a display device, or other input/output devices (notshown) coupled to the standard I/O bus 708. Collectively, these elementsare intended to represent a broad category of computer hardware systems,including but not limited to computer systems based on thex86-compatible processors manufactured by Intel Corporation of SantaClara, Calif., and the x86-compatible processors manufactured byAdvanced Micro Devices (AMD), Inc., of Sunnyvale, Calif., as well as anyother suitable processor.

An operating system manages and controls the operation of the computersystem 700, including the input and output of data to and from softwareapplications (not shown). The operating system provides an interfacebetween the software applications being executed on the system and thehardware components of the system. Any suitable operating system may beused, such as the LINUX Operating System, the Apple Macintosh OperatingSystem, available from Apple Computer Inc. of Cupertino, Calif., UNIXoperating systems, Microsoft® Windows® operating systems, BSD operatingsystems, and the like. Other implementations are possible.

The elements of the computer system 700 are described in greater detailbelow. In particular, the network interface 716 provides communicationbetween the computer system 700 and any of a wide range of networks,such as an Ethernet (e.g., IEEE 802.3) network, a backplane, etc. Themass storage 718 provides permanent storage for the data and programminginstructions to perform the above-described processes and featuresimplemented by the respective computing systems identified above,whereas the system memory 714 (e.g., DRAM) provides temporary storagefor the data and programming instructions when executed by the processor702. The I/O ports 720 may be one or more serial and/or parallelcommunication ports that provide communication between additionalperipheral devices, which may be coupled to the computer system 700.

The computer system 700 may include a variety of system architectures,and various components of the computer system 700 may be rearranged. Forexample, the cache 704 may be on-chip with processor 702. Alternatively,the cache 704 and the processor 702 may be packed together as a“processor module”, with processor 702 being referred to as the“processor core”. Furthermore, certain embodiments of the invention mayneither require nor include all of the above components. For example,peripheral devices coupled to the standard I/O bus 708 may couple to thehigh performance I/O bus 706. In addition, in some embodiments, only asingle bus may exist, with the components of the computer system 700being coupled to the single bus. Moreover, the computer system 700 mayinclude additional components, such as additional processors, storagedevices, or memories.

In general, the processes and features described herein may beimplemented as part of an operating system or a specific application,component, program, object, module, or series of instructions referredto as “programs”. For example, one or more programs may be used toexecute specific processes described herein. The programs typicallycomprise one or more instructions in various memory and storage devicesin the computer system 700 that, when read and executed by one or moreprocessors, cause the computer system 700 to perform operations toexecute the processes and features described herein. The processes andfeatures described herein may be implemented in software, firmware,hardware (e.g., an application specific integrated circuit), or anycombination thereof.

In one implementation, the processes and features described herein areimplemented as a series of executable modules run by the computer system700, individually or collectively in a distributed computingenvironment. The foregoing modules may be realized by hardware,executable modules stored on a computer-readable medium (ormachine-readable medium), or a combination of both. For example, themodules may comprise a plurality or series of instructions to beexecuted by a processor in a hardware system, such as the processor 702.Initially, the series of instructions may be stored on a storage device,such as the mass storage 718. However, the series of instructions can bestored on any suitable computer readable storage medium. Furthermore,the series of instructions need not be stored locally, and could bereceived from a remote storage device, such as a server on a network,via the network interface 716. The instructions are copied from thestorage device, such as the mass storage 718, into the system memory 714and then accessed and executed by the processor 702. In variousimplementations, a module or modules can be executed by a processor ormultiple processors in one or multiple locations, such as multipleservers in a parallel processing environment.

Examples of computer-readable media include, but are not limited to,recordable type media such as volatile and non-volatile memory devices;solid state memories; floppy and other removable disks; hard diskdrives; magnetic media; optical disks (e.g., Compact Disk Read-OnlyMemory (CD ROMS), Digital Versatile Disks (DVDs)); other similarnon-transitory (or transitory), tangible (or non-tangible) storagemedium; or any type of medium suitable for storing, encoding, orcarrying a series of instructions for execution by the computer system700 to perform any one or more of the processes and features describedherein.

For purposes of explanation, numerous specific details are set forth inorder to provide a thorough understanding of the description. It will beapparent, however, to one skilled in the art that embodiments of thedisclosure can be practiced without these specific details. In someinstances, modules, structures, processes, features, and devices areshown in block diagram form in order to avoid obscuring the description.In other instances, functional block diagrams and flow diagrams areshown to represent data and logic flows. The components of blockdiagrams and flow diagrams (e.g., modules, blocks, structures, devices,features, etc.) may be variously combined, separated, removed,reordered, and replaced in a manner other than as expressly describedand depicted herein.

Reference in this specification to “one embodiment”, “an embodiment”,“other embodiments”, “one series of embodiments”, “some embodiments”,“various embodiments”, or the like means that a particular feature,design, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the disclosure. Theappearances of, for example, the phrase “in one embodiment” or “in anembodiment” in various places in the specification are not necessarilyall referring to the same embodiment, nor are separate or alternativeembodiments mutually exclusive of other embodiments. Moreover, whetheror not there is express reference to an “embodiment” or the like,various features are described, which may be variously combined andincluded in some embodiments, but also variously omitted in otherembodiments. Similarly, various features are described that may bepreferences or requirements for some embodiments, but not otherembodiments.

The language used herein has been principally selected for readabilityand instructional purposes, and it may not have been selected todelineate or circumscribe the inventive subject matter. It is thereforeintended that the scope of the invention be limited not by this detaileddescription, but rather by any claims that issue on an application basedhereon. Accordingly, the disclosure of the embodiments of the inventionis intended to be illustrative, but not limiting, of the scope of theinvention, which is set forth in the following claims.

What is claimed is:
 1. A computer-implemented method comprising:identifying, by a computing system, a set of participants in a groupvideo call, wherein each participant is associated with an uplinkcapacity and a downlink capacity, and the set of participants includes aset of sender participants; ranking, by the computing system, the set ofsender participants based on uplink capacities for the set of senderparticipants; and sequentially processing, by the computing system, theset of sender participants in an order based on the ranking todetermine, for each sender participant of the set of senderparticipants, one or more video stream layers to be uploaded by thesender participant.
 2. The computer-implemented method of claim 1,wherein the set of participants includes a set of subscriberparticipants.
 3. The computer-implemented method of claim 2, furthercomprising: for each subscriber participant of the set of subscriberparticipants, assigning the subscriber participant to receive at leastone video stream layer from at least one sender participant of the setof sender participants.
 4. The computer-implemented method of claim 3,wherein each video stream layer to be uploaded by a sender participantof the set of sender participants is associated with a bitrate.
 5. Thecomputer-implemented method of claim 4, wherein the bitrate for eachvideo stream layer to be uploaded by each sender participant of the setof sender participants is determined based on downlink capacities ofsubscriber participants subscribed to the sender participant.
 6. Thecomputer-implemented method of claim 4, wherein the bitrate for eachvideo stream layer to be uploaded by each sender participant of the setof sender participants is determined based on downlink capacities ofsubscriber participants subscribed to the sender participant and theuplink capacity of the sender participant.
 7. The computer-implementedmethod of claim 3, wherein the sequentially processing the set of senderparticipants comprises: for a first sender participant of the set ofsender participants, identifying, from the set of subscriberparticipants, one or more subscriber participants subscribed to thefirst sender participant, ranking the one or more subscriberparticipants subscribed to the first sender participant, andsequentially processing the one or more subscriber participantssubscribed to the first sender participant in an order based on theranking to assign, for each subscriber participant of the one or moresubscriber participants subscribed to the first sender participant, thesubscriber participant to one video stream layer to be uploaded by thefirst sender participant.
 8. The computer-implemented method of claim 7,wherein the one or more subscriber participants subscribed to the firstsender participant are ranked based on downlink capacities.
 9. Thecomputer-implemented method of claim 8, wherein the one or moresubscriber participants subscribed to the first sender participant areranked in ascending order based on downlink capacities.
 10. Thecomputer-implemented method of claim 7, wherein the sequentiallyprocessing the one or more subscriber participants subscribed to thefirst sender participant comprises, for each subscriber participant ofthe one or more subscriber participants subscribed to the first senderparticipant, determining whether to create a new layer to be uploaded bythe first sender participant or assigning the subscriber participant toa previously created layer associated with the first sender participant.11. A system comprising: at least one processor; and a memory storinginstructions that, when executed by the at least one processor, causethe system to perform a method comprising: identifying a set ofparticipants in a group video call, wherein each participant isassociated with an uplink capacity and a downlink capacity, and the setof participants includes a set of sender participants; ranking the setof sender participants based on uplink capacities for the set of senderparticipants; and sequentially processing the set of sender participantsin an order based on the ranking to determine, for each senderparticipant of the set of sender participants, one or more video streamlayers to be uploaded by the sender participant.
 12. The system of claim11, wherein the set of participants includes a set of subscriberparticipants.
 13. The system of claim 12, wherein the instructions, whenexecuted by the at least one processor, further cause the system toperform: for each subscriber participant of the set of subscriberparticipants, assigning the subscriber participant to receive at leastone video stream layer from at least one sender participant of the setof sender participants.
 14. The system of claim 13, wherein each videostream layer to be uploaded by a sender participant of the set of senderparticipants is associated with a bitrate.
 15. The system of claim 14,wherein the bitrate for each video stream layer to be uploaded by eachsender participant of the set of sender participants is determined basedon downlink capacities of subscriber participants subscribed to thesender participant.
 16. A non-transitory computer-readable storagemedium including instructions that, when executed by at least oneprocessor of a computing system, cause the computing system to perform amethod comprising: identifying a set of participants in a group videocall, wherein each participant is associated with an uplink capacity anda downlink capacity, and the set of participants includes a set ofsender participants; ranking the set of sender participants based onuplink capacities for the set of sender participants; and sequentiallyprocessing the set of sender participants in an order based on theranking to determine, for each sender participant of the set of senderparticipants, one or more video stream layers to be uploaded by thesender participant.
 17. The non-transitory computer-readable storagemedium of claim 16, wherein the set of participants includes a set ofsubscriber participants.
 18. The non-transitory computer-readablestorage medium of claim 17, wherein the instructions, when executed byat least one processor of a computing system, further cause thecomputing system to perform: for each subscriber participant of the setof subscriber participants, assigning the subscriber participant toreceive at least one video stream layer from at least one senderparticipant of the set of sender participants.
 19. The non-transitorycomputer-readable storage medium of claim 18, wherein each video streamlayer to be uploaded by a sender participant of the set of senderparticipants is associated with a bitrate.
 20. The non-transitorycomputer-readable storage medium of claim 19, wherein the bitrate foreach video stream layer to be uploaded by each sender participant of theset of sender participants is determined based on downlink capacities ofsubscriber participants subscribed to the sender participant.